Method and Network Monitoring Probe for Tracking Identifiers Corresponding to a User Device in Wireless Communication Network

1. A method for tracking identifiers corresponding to a user device by a network monitoring probe connected with a source base station, a target base station, a source mobility management entity device (MME) and a target MME in a wireless communication network, comprising: monitoring the source base station by the network monitoring probe, for receipt of a first control plane packet data unit (PDU) comprising at least a first control plane message transmitted from the source base station to the source MME, the first control plane message including at least a first control plane identifier of the source base station, and a first user device identifier of the user device; monitoring the source MME by the network monitoring probe, for receipt of a second control plane message transmitted from the source MME to the target MME, which comprises at least a second control plane identifier of the source base station, a second user device identifier and a third user device identifier wherein the second and the third user device identifiers uniquely identify the user device in the wireless communication network; in response to receipt of the second control plane message, comparing the first control plane identifier of the source base station to the second control plane identifier of the source base station, comparing the first user device identifier to the second user device identifier, and determining whether the first control plane message is a handover required message; and in response to a determination that the first control plane identifier is identical to the second control plane identifier, the first user device identifier is identical to the second user device identifier and the first control plane message is a handover required message, storing in the network monitoring probe or an external management device the first user device identifier and the third user device identifier respectively as an identified first user device identifier and an identified second user device identifier of the user device, and determining that the user device commences a S1-based handover; wherein: the first control plane identifier is a cell global identifier (CGI) of the source base station; the second control plane identifier is a CGI of the source base station; the first user device identifier is a radio network temporary identifier (RNTI) of the user device; the second user device identifier is a RNTI of a user device; the third user device identifier is an International Mobile Subscriber Identity (IMSI) of a user device; the first control plane PDU is a S1 Application Protocol PDU; the first control plane message is a handover required message transmitted from the source base station to the source MME; and the second control plane message is a forward relocation request message transmitted from the source MME to the target MME.

2. The method of claim 1 , wherein the first control plane message further comprises a third control plane identifier of the target base station, the method further comprising: in response to a determination that the first control plane identifier is identical to the third control plane identifier, the first user device identifier is identical to the second user device identifier and the first control plane message is a handover required message, storing in the network monitoring probe or an external management device the third control plane identifier of the target base station which the user device is to be handed over.

3. The method of claim 2 , further comprising: monitoring the target MME connected with the source MME, by the network monitoring probe, for receipt of a second control plane PDU comprising at least a fourth control plane identifier, a fifth control plane identifier, and at least a third control plane message transmitted from the target MME to the target base station, which comprises at least a sixth control plane identifier and a fourth user device identifier; in response to receipt of the third control plane message in the second control plane PDU, comparing the sixth control plane identifier to the first control plane identifier of the first control plane message and comparing the fourth user device identifier to the first user device identifier of the first control plane message; and in response to a determination that the sixth control plane identifier is identical to the second control plane identifier of the first control plane message and the fourth user device identifier is identical to the first user device identifier of the first control plane message, storing in the network monitoring probe or an external management device the fourth control plane identifier to be a control plane identifier assigned by the target base station to the user device, the fifth control plane identifier to be a control plane identifier assigned by the target MME to the user device.

4. The method of claim 3 , wherein: the third control plane message is a handover request message transmitted from the target MME to the target base station; the sixth control plane identifier of the third control plane message is a last visited CGI of a base station corresponding to the user device; and the fourth user device identifier of the third control plane message is the RNTI assigned to the user device by the source base station.

5. The method of claim 4 , wherein: the second control plane PDU is S1AP PDU; the fourth control plane identifier is a control plane evolved NodeB UE S1 Application Protocol Identifier (eNB-UE-S1AP-ID) assigned by the target base station to the user device; and the fifth control plane identifier is a control plane MME UE S1 Application Protocol Identifier (MME-UE-S1AP-ID) assigned by the target MME to the user device.

6. The method of claim 5 , wherein the first control plane PDU further comprises a seventh and an eighth control plane identifiers, the method further comprising: in response to a determination that first control plane identifier is identical to the second control plane identifier and the first user device identifier is identical to the second user device identifier, storing in the network monitoring probe or an external management device the seventh control plane identifier of the first control plane PDU to be a control plane eNB-UE-S1AP-ID assigned by the source base station to the user device, and storing or outputting the eighth control plane identifier of the first control plane PDU to be a MME-UE-S1AP-ID assigned by the source MME to the user device.

7. The method of claim 6 , further comprising: monitoring the target base station by the network monitoring probe, for receipt of a third control plane PDU comprising at least a ninth and a tenth control plane identifier, and a fourth control plane message transmitted from the target base station to the target MME, which comprises at least a fifth user device identifier; comparing the ninth control plane identifier to the fourth control plane identifier of the second control plane PDU, and comparing the tenth control plane identifier to the fifth control plane identifier of the second control plane PDU; and in response to a determination that the ninth control plane identifier is identical to the fourth control plane identifier of the second control plane PDU, and the tenth user device identifier is identical to the fifth control plane identifier of the second control plane PDU, storing in the network monitoring probe or an external management device the fifth user device identifier to be an identified third user device identifier of the user device.

8. The method of claim 7 , wherein: the third control plane PDU is S1AP PDU; the fourth control plane message is a handover request acknowledgement message transmitted from the target base station to the target MME; the fifth user identifier is a new user device identifier assigned by the target base station; the ninth user device identifier is a control plane eNB-UE-S1AP-ID assigned by the target base station to the user device; and the tenth control plane identifier is a MME-UE-S1AP-ID assigned by the target MME to the user device.

9. The method of claim 8 , further comprising: monitoring the target base station by the network monitoring probe, for receipt of a fourth control plane PDU comprising at least an eleventh and a twelfth control plane identifiers and a fifth control plane message transmitted from the target base station to the target MME; determining whether the fifth control plane message is a handover notify message; comparing the eleventh control plane identifier to the fourth control plane identifier of the second control plane PDU, and comparing the twelfth control plane identifier to the fifth control plane identifier of the second control plane PDU; and in response to a determination that the fifth control plane message is the handover notify message, the eleventh control plane identifier is identical to the fourth control plane identifier of the second control plane PDU, and the twelfth control plane identifier is identical to the fifth control plane identifier of the second control plane PDU, storing or outputting the fourth control plane identifier of the second control plane PDU to be a control plane eNB-UE-S1AP-ID assigned to the user device by a current serving base station of the user device, and storing in the network monitoring probe or an external management device the fifth control plane identifier of the second control plane PDU to be a control plane MME-UE-S1AP-ID assigned to the user device by a current serving MME of the user device.

10. The method of claim 9 , further comprising: in response to a determination that the fifth control plane message is the handover notify message, the eleventh control plane identifier is identical to the fourth control plane identifier of the second control plane PDU, and the twelfth user device identifier is identical to the fifth control plane identifier of the second control plane PDU, storing or outputting the fifth user identifier of the user device to be a RNTI assigned by the current serving base station of the user device which replaces the identified first user device identifier of the user device.

11. A network monitoring probe for tracking identifiers corresponding to a user device, wherein the network monitoring probe connected with a source base station, a target base station, a source mobility management entity device (MME) and a target MME in wireless communication network, the network monitoring probe comprising: a control plane message monitor, configured to monitor the source base station for receipt of a first control plane packet data unit (PDU) comprising at least a first control plane message transmitted from the source base station to the source MME, which comprises at least a first control plane identifier of the source base station, and a first user device identifier of the user device; the control plane message monitor, further configured to monitor the source MME for receipt of a second control plane message transmitted from the source MME to the target MME, the second control plane message including at least a second control plane identifier of the source base station, a second user device identifier and a third user device identifier wherein the second and the third user device identifiers uniquely identify the user device in the wireless communication network; the control plane message monitor, further configured to determine whether the first control plane message is a handover required message; an identifier comparator, configured to compare the first control plane identifier of the source base station to the second control plane identifier of the source base station and compare the first user device identifier to the second user device identifier; an identifier output, configured to output to a storage unit within the network monitoring probe or a management device external to the network monitoring probe, the first user device identifier of the first control plane message and the third user device identifier of the second control plane message as identified first user device identifier and identified second user device identifier of the user device, in response to a determination that the first control plane identifier is identical to the second control plane identifier and the first user device identifier is identical to the second user device identifier; and the identifier comparator, further configured to determine that the user device with the identified first and the second user device identifiers commences a S1-based handover, in response to the determination that first control plane identifier is identical to the third control plane identifier, the first user device identifier is identical to the second user device identifier, and the first control plane message is the handover required message; the first control plane identifier is a cell global identifier (CGI) of the source base station; the second control plane identifier is a CGI of a base station; the first control plane message further comprises a third control plane identifier which is a CGI of the target base station to which the user device is to be handed over; the first user device identifier is a radio network temporary identifier (RNTI) of the user device; the second user device identifier is a RNTI of a user device; the first control plane PDU is a S1 Application Protocol PDU; the first control plane message is a handover request message transmitted from the source base station to the source MME; the second control plane message is a forward relocation request message transmitted from the source the source MME to the target MME; and the third user device identifier is an International Mobile Subscriber Identity (IMSI) of a user device.

12. The network monitoring probe of claim 11 , wherein: the control plane message monitor, further configured to monitor the target MME connected with the source MME for receipt of a second control plane PDU comprising at least a fourth control plane identifier, a fifth control plane identifier, and at least a third control plane message transmitted from the target MME to the target base station, which comprises at least a sixth control plane identifier and a fourth user device identifier; the identifier comparator, further configured to compare the sixth control plane identifier to the first control plane identifier of the first control plane message and comparing the fourth user device identifier to the first user device identifier of the first control plane message, in response to receipt of the third control plane message in the second control plane PDU; and the identifier output, further configured to output to a storage unit of the network monitoring probe or a management device external to the network monitoring probe, the fourth control plane identifier to be a control plane identifier assigned by the target base station to the user device and output the fifth control plane identifier to be a control plane identifier assigned by the target MME to the user device, in response to a determination that the sixth control plane identifier is identical to the second control plane identifier of the first control plane message and the fourth user device identifier is identical to the first user device identifier of the first control plane message.

13. The network monitoring probe of claim 12 , wherein: the third control plane message is a handover request message transmitted from the target MME to the target base station; the sixth control plane identifier of the third control plane message is a last visited CGI of a base station corresponding to the user device; the fourth user device identifier of the third control plane message is the RNTI assigned to the user device by the source base station; the second control plane PDU is S1AP PDU; the fourth control plane identifier is a eNB-UE-S1AP-ID assigned by the target base station to the user device; and the fifth control plane identifier is a MME-UE-S1AP-ID assigned by the target MME to the user device.

14. The network monitoring probe of claim 13 , wherein: the first control plane PDU further comprises a seventh and an eighth control plane identifiers; and the identifier output, further configured to output to a storage unit of the network monitoring probe or a management device external to the network monitoring probe, the seventh control plane identifier of the first control plane PDU to be a control plane eNB-UE-S1AP-ID assigned by the source base station to the user device, and output the eighth control plane identifier of the first control plane PDU to be a control plane MME-UE-S1AP-ID assigned by the source MME to the user device, in response to a determination that first control plane identifier is identical to the third control plane identifier and the first user device identifier is identical to the second user device identifier.

15. The network monitoring probe of claim 14 , wherein: the control plane message monitor, further configured to monitor the target base station for receipt of a third control plane PDU comprising at least a ninth and a tenth control plane identifier, and a fourth control plane message transmitted from the target base station to the target MME, which comprises at least a fifth user device identifier; the identifier comparator, further configured to compare the ninth control plane identifier to the fourth control plane identifier of the second control plane PDU, and comparing the tenth control plane identifier to the fifth control plane identifier of the second control plane PDU, in response to receipt of the fourth control plane message; and the identifier output further configured to output to a storage unit of the network monitoring probe or a management device external to the network monitoring probe, the fifth user device identifier to be an identified third user device identifier of the user device, in response to a determination that the ninth control plane identifier is identical to the fourth control plane identifier of the second control plane PDU, and the tenth user device identifier is identical to the fifth control plane identifier of the second control plane PDU.

16. The network monitoring probe of claim 15 , wherein: the third control plane PDU is S1AP PDU; the fourth control plane message is a handover request acknowledgement message transmitted from the target base station to the target MME; the fifth user identifier is a new user device identifier assigned by the target base station; the ninth user device identifier is a control plane eNB-UE-S1AP-ID assigned by the target base station to the user device; and the tenth control plane identifier is a MME-UE-S1AP-ID assigned by the target MME to the user device.

17. The network monitoring probe of claim 16 , wherein: the control plane message monitor, further configured to monitor the target base station for receipt of a fourth control plane PDU comprising at least an eleventh and a twelfth control plane identifiers and a fifth control plane message transmitted from the target base station to the target MME; the control plane message monitor, further configured to determine whether the fifth control plane message is a handover notify message; the identifier comparator, further configured to compare the eleventh control plane identifier to the fourth control plane identifier of the second control plane PDU, and comparing the twelfth control plane identifier to the fifth control plane identifier of the second control plane PDU, in response to receipt of the fifth control plane message; and the identifier output, further configured to output to a storage unit of the network monitoring probe or a management device external to the network monitoring probe, the fourth control plane identifier of the second control plane PDU to be a control plane eNB-UE-S1AP-ID assigned to the user device by a current serving base station of the user device, and outputting the fifth control plane identifier of the second control plane PDU to be a control plane MME-UE-S1AP-ID assigned to the user device by a current serving MME of the user device, in response to a determination that the fifth control plane message is the handover notify message, the eleventh control plane identifier is identical to the fourth control plane identifier of the second control plane PDU, and the twelfth control plane identifier is identical to the fifth control plane identifier of the second control plane PDU.

18. The network monitoring probe of claim 17 , wherein: the identifier output, further configured to output to a storage unit of the network monitoring probe or a management device external to the network monitoring probe, the fifth user identifier of the user device to be a RNTI assigned by the current serving base station of the user device which replaces the identified first user device identifier of the user device, in response to a determination that the fifth control plane message is the handover notify message, the eleventh control plane identifier is identical to the fourth control plane identifier of the third control plane message, and the twelfth control plane identifier is identical to the fifth control plane identifier of the third control plane message.